re·duc·ti·o ad ab·sur·dum (rĭ-dŭktē-ō ăd əb-sûrdəm, -zûr-, -shē-ō)
n. pl. re·duc·ti·o·nes ad absurdum (-ōnēz, -nās)
Disproof of a proposition by showing that it leads to absurd or untenable conclusions.
[Medieval Latin reductiō ad absurdum : Latin reductiō, a bringing back, reduction + Latin ad, to + Latin absurdum, absurdity, from neuter of absurdus, absurd.]
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Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.